class Animal(object):
    pass

class Mammal(Animal):
    pass

class Bird(Animal):
    pass

class Dog(Mammal):
    pass

class Bat(Mammal):
    pass

class Parrot(Bird):
    pass

class Ostrich(Bird):
    pass

class RunnableMixin(object):
    def run(self):
        print('Running....')

class FlyableMixin(object):
    def fly(self):
        print('Flying....')

class CarnivorousMixin(object):
    pass


class Dog(Mammal,RunnableMixin):
    pass

class Bat(Mammal,FlyableMixin,CarnivorousMixin):
    pass

dog = Dog()
dog.run()
bird = Bat()
bird.fly()
